Multiple Vulnerabilities in Cisco Security Products Could Allow for Arbitrary Code Execution

Multiple vulnerabilities have been discovered in Cisco security products that could allow for arbitrary code execution.

• Cisco Secure Firewall Management Center (FMC) is a centralized management solution for Cisco Secure Firewall devices, enabling policy control, event monitoring, and threat analysis.
• Cisco Firepower 2100 Series is a family of threat-focused firewalls designed for high-performance security and visibility across enterprise networks.
• Cisco Secure Firewall ASA Software is a firewall software platform that delivers advanced threat protection, VPN services, and access control.
• Cisco Secure Firewall Threat Defense (FTD) Software is an integrated threat management solution combining firewall, IPS, and malware protection capabilities.
• Cisco Identity Services Engine (ISE) is a policy-based access control and identity management system that enforces network segmentation and compliance.
• Cisco IOS Software is the foundational operating system for Cisco networking devices, providing routing, switching, and network services.
• Cisco IOS XE Software is a modular and programmable network OS designed for enterprise-grade routers and switches with enhanced automation and security features.

Successful exploitation of the most severe of these vulnerabilities could allow for arbitrary code execution in the context of the user associated with the service. Depending on the privileges associated with the account, an attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than those who operate with administrative user rights.

Multiple vulnerabilities have been discovered in Cisco security products, the most severe of which could allow for arbitrary code execution. Details of the vulnerabilities are as follows:

Tactic: Initial Access (TA0001):

Technique: Exploit Public-Facing Application (T1190):

• A vulnerability in the RADIUS subsystem implementation of Cisco Secure Firewall Management Center (FMC) Software could allow an unauthenticated, remote attacker to inject arbitrary shell commands that are executed by the device. (CVE-2025-20265)

Additional lower severity vulnerabilities include:

• A vulnerability in the packet inspection functionality of the Snort 3 Detection Engine of Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. (CVE-2025-20217)
• A vulnerability in the RADIUS proxy feature for the IPsec VPN feature of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS). (CVE-2025-20222)
• A vulnerability in the web-based management interface of Cisco Secure Firewall Management Center (FMC) Software could allow an authenticated, remote attacker to inject arbitrary HTML content into a device-generated document. (CVE-2025-20148)
• A vulnerability in the Remote Access SSL VPN service for Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow a remote attacker that is authenticated as a VPN user to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition. (CVE-2025-20244)
• Multiple vulnerabilities in the management and VPN web servers for Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to stop responding or reload unexpectedly, resulting in a denial of service (DoS) condition. (CVE-2025-20243, CVE-2025-20133)
• A vulnerability in the certificate processing of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition. (CVE-2025-20134)
• A vulnerability in the function that performs IPv4 and IPv6 Network Address Translation (NAT) DNS inspection for Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, resulting in a denial of service (DoS) condition. (CVE-2025-20136)
• A vulnerability in the Remote Access SSL VPN service for Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an authenticated, remote attacker to create or delete arbitrary files on the underlying operating system. If critical system files are manipulated, new Remote Access SSL VPN sessions could be denied and existing sessions could be dropped, causing a denial of service (DoS) condition. An exploited device requires a manual reboot to recover. (CVE-2025-20251)
• Multiple vulnerabilities in the Internet Key Exchange Version 2 (IKEv2) feature of Cisco IOS Software, Cisco IOS XE Software, Cisco Secure Firewall Adaptive Security Appliance (ASA) Software, and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a denial of service (DoS) condition. (CVE-2025-20224, CVE-2025-20225, CVE-2025-20239, CVE-2025-20252, CVE-2025-20253, CVE-2025-20254)
• A vulnerability in the web services interface of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a buffer overflow on an affected system. (CVE-2025-20263)
• A vulnerability in the TLS 1.3 implementation for a specific cipher for Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software for Cisco Firepower 3100 and 4200 Series devices could allow an authenticated, remote attacker to consume resources that are associated with incoming TLS 1.3 connections, which eventually could cause the device to stop accepting any new SSL/TLS or VPN requests. (CVE-2025-20127)
• A vulnerability in the Geolocation-Based Remote Access (RA) VPN feature of Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to bypass configured policies to allow or deny HTTP connections based on a country or region. (CVE-2025-20268)
• A vulnerability in the web-based management interface of Cisco Secure Firewall Management Center (FMC) Software could allow an unauthenticated, remote attacker to conduct a cross-site scripting (XSS) attack against a user of the interface. (CVE-2025-20235)
• A vulnerability in the web-based management interface of Cisco Secure Firewall Management Center (FMC) Software could allow an authenticated, remote attacker to retrieve sensitive information from an affected device. (CVE-2025-20218)
• A vulnerability in the CLI of Cisco Secure Firewall Management Center (FMC) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an authenticated, local attacker to execute arbitrary commands on the underlying operating system as root.(CVE-2025-20220)
• A vulnerability in the web-based management interface of Cisco Secure Firewall Management Center (FMC) Software could allow an authenticated, remote attacker with Administrator-level privileges to execute arbitrary commands on the underlying operating system. (CVE-2025-20306)
• Multiple vulnerabilities in the web-based management interface of Cisco Secure Firewall Management Center (FMC) Software could allow an authenticated, remote attacker to access files that they are not authorized to access.(CVE-2025-20301, CVE-2025-20302)
• A vulnerability in the DHCP client functionality of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, adjacent attacker to exhaust available memory. (CVE-2025-20135)
• Multiple vulnerabilities in Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an authenticated, local attacker to execute arbitrary commands on the underlying operating system with root-level privileges. To exploit these vulnerabilities, the attacker must have valid administrative credentials. (CVE-2025-20237, CVE-2025-20238)
• A vulnerability in the implementation of access control rules for loopback interfaces in Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to send traffic that should have been blocked to a loopback interface. (CVE-2025-20219)

Successful exploitation of the most severe of these vulnerabilities could allow for arbitrary code execution in the context of the user associated with the service.Depending on the privileges associated with the account, an attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than those who operate with administrative user rights.

We recommend the following actions be taken:

• Apply appropriate updates provided by Cisco to vulnerable systems immediately after appropriate testing. (M1051: Update Software)
• Safeguard 7.1 : Establish and Maintain a Vulnerability Management Process: Establish and maintain a documented vulnerability management process for enterprise assets. Review and update documentation annually, or when significant enterprise changes occur that could impact this Safeguard.
• Safeguard 7.2: Establish and Maintain a Remediation Process:Establish and maintain a risk-based remediation strategy documented in a remediation process, with monthly, or more frequent, reviews.
• Safeguard 7.4: Perform Automated Application Patch Management:Perform application updates on enterprise assets through automated patch management on a monthly, or more frequent, basis.
• Safeguard 7.5 : Perform Automated Vulnerability Scans of Internal Enterprise Assets: Perform automated vulnerability scans of internal enterprise assets on a quarterly, or more frequent, basis. Conduct both authenticated and unauthenticated scans, using a SCAP-compliant vulnerability scanning tool.
• Safeguard 7.7: Remediate Detected Vulnerabilities:Remediate detected vulnerabilities in software through processes and tooling on a monthly, or more frequent, basis, based on the remediation process.
• Safeguard 12.1: Ensure Network Infrastructure is Up-to-Date:Ensure network infrastructure is kept up-to-date. Example implementations include running the latest stable release of software and/or using currently supported network-as-a-service (NaaS) offerings. Review software versions monthly, or more frequently, to verify software support.
• Safeguard 18.1: Establish and Maintain a Penetration Testing Program:Establish and maintain a penetration testing program appropriate to the size, complexity, and maturity of the enterprise. Penetration testing program characteristics include scope, such as network, web application, Application Programming Interface (API), hosted services, and physical premise controls; frequency; limitations, such as acceptable hours, and excluded attack types; point of contact information; remediation, such as how findings will be routed internally; and retrospective requirements.
• Safeguard 18.2: Perform Periodic External Penetration Tests:Perform periodic external penetration tests based on program requirements, no less than annually. External penetration testing must include enterprise and environmental reconnaissance to detect exploitable information. Penetration testing requires specialized skills and experience and must be conducted through a qualified party. The testing may be clear box or opaque box.
• Safeguard 18.3: Remediate Penetration Test Findings:Remediate penetration test findings based on the enterprise’s policy for remediation scope and prioritization.

• Apply the Principle of Least Privilege to all systems and services. Run all software as a non-privileged user (one without administrative privileges) to diminish the effects of a successful attack. (M1026: Privileged Account Management)
• Safeguard 4.7: Manage Default Accounts on Enterprise Assets and Software:Manage default accounts on enterprise assets and software, such as root, administrator, and other pre-configured vendor accounts. Example implementations can include: disabling default accounts or making them unusable.
• Safeguard 5.5: Establish and Maintain an Inventory of Service Accounts:Establish and maintain an inventory of service accounts. The inventory, at a minimum, must contain department owner, review date, and purpose. Perform service account reviews to validate that all active accounts are authorized, on a recurring schedule at a minimum quarterly, or more frequently.

• Vulnerability scanning is used to find potentially exploitable software vulnerabilities to remediate them. (M1016:Vulnerability Scanning)
• Safeguard 16.13: Conduct Application Penetration Testing:Conduct application penetration testing. For critical applications, authenticated penetration testing is better suited to finding business logic vulnerabilities than code scanning and automated security testing. Penetration testing relies on the skill of the tester to manually manipulate an application as an authenticated and unauthenticated user.

• Architect sections of the network to isolate critical systems, functions, or resources. Use physical and logical segmentation to prevent access to potentially sensitive systems and information. Use a DMZ to contain any internet-facing services that should not be exposed from the internal network. Configure separate virtual private cloud (VPC) instances to isolate critical cloud systems. (M1030:Network Segmentation)
• Safeguard 12.2: Establish and Maintain a Secure Network Architecture: Establish and maintain a secure network architecture. A secure network architecture must address segmentation, least privilege, and availability, at a minimum.

• Use capabilities to detect and block conditions that may lead to or be indicative of a software exploit occurring. (M1050:Exploit Protection)
• Safeguard 10.5:Enable Anti-Exploitation Features:Enable anti-exploitation features on enterprise assets and software, where possible, such as Microsoft® Data Execution Prevention (DEP), Windows® Defender Exploit Guard (WDEG), or Apple® System Integrity Protection (SIP) and Gatekeeper™.